Did the sheet of plastic that came with the Interface Unit serve a purpose?

Hey guys, just wondering if someone can answer a question about the the sheet of transparent plastic that's stuck with two squares of masking tape to the CD-ROM2 side of the Interface Unit. Does it serve some kind of purpose? I would have thought shielding or isolation, but the only metal parts in this area are the grounding pins on the Interface Unit itself and the CD-ROM2, everything else is plastic on plastic. :suspicion: About the only way I've found it to be useful was the masking tape, well, masked, some of the plastic and kept it out of the sun, giving me a benchmark for the unit's original color when I was refurbishing it

 

Any pix of this sheet you're referring?

 

Yeah, I just picked one of these up and I'm not totally sure what you are referring to. I bought mine loose though, so whatever you are referring to might have been lost in time...

 

This thing (currently stuck to the bottom of the console, but whatever):


Obviously, it's not important, since I've since seen a lot of consoles that are missing it, and it works fine without it (as it should, since it's just plastic on plastic). But I still find it odd that it's got the little notches in it so it can be in place and still allow the CD-ROM to be used. Plus, it's held in place with masking tape, which is much stronger than the tape they normally use for packaging.

 

I don't think this is supposed to be stick on the back side of the IFU with tape, nor have I ever seen this before.

My guess is, that this sheet was originally supposed to be inside the IFU case to prevent short circuits between the PCB and other parts.
If you open the CD-ROM f.e, you would see the very same sheet used exactly for that reason.

 

No no, it was originally stuck to the area of the IFU that the CD-ROM sits on, I just stick it to the underside for storage. See the two notches in the plastic? As I mentioned, this allows the plastic sheet to stay in place, even when the CD-ROM is attached (the notch goes around the grounding connector). As I said, it seems kinda useless, since the plastic sheet is essentially preventing the plastic of the IFU from touching the plastic of the CD-ROM. It's probably nothing more than packaging, but I do find it weird it's designed to be able to stay in place even when everything is unpacked and assembled.

 

the plastic sheet is to stop the 2nd gear from crumbling, just joking.
I got it with the cdrom2 which I purchased new, probably just packaging, but as you say it seems designed to stay in the unit especially as it has the slots for the earthing connector / springy ball-bearings.

 

Cool, I see

 

My x68000 compact has one too, but it appears to serve the purpose of preventing the motherboard from shorting with the metal shielding. You say your machine has no shielding so its kind of funny.

 

The second PC Engine with CD-ROM I brought didn't come with the sheet, so clearly it's packing. Still, it's strange that this packing is designed to be able to be left in place without effecting the operation of the console.